On Mon, 23 Mar 2020 15:47:41 +0900 Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote: > Hi Taeung, > > On Sun, 22 Mar 2020 23:06:20 +0900 > Taeung Song <treeze.taeung@xxxxxxxxx> wrote: > > > Hi, > > > > After setting 'maxactive' for kretprobe, > > how can I recheck the value of 'maxactive' ? > > For example, in order to distinguish the difference > > between two kretprobe events > > (kmem_cache_alloc_node and kmem_cache_alloc_node10) > > > > $ cd /sys/kernel/debug/tracing > > $ echo 'r:kmem_cache_alloc_node kmem_cache_alloc_node' >> kprobe_events > > $ echo 'r10:kmem_cache_alloc_node10 kmem_cache_alloc_node' >> > > kprobe_events > > > > $ cat kprobe_events > > r:kprobes/kmem_cache_alloc_node kmem_cache_alloc_node > > r:kprobes/kmem_cache_alloc_node10 kmem_cache_alloc_node > > Oops! good catch. That must be a bug, since the kprobe_events design policy > is to support following operation. > > $ cat kprobe_events > /etc/event_setting > (reboot) > $ cat /etc/event_setting > kprobe_events > > What about below patch? > > >From 935ed56819f2bfb7ac977f5c63273c9a6e3dfb42 Mon Sep 17 00:00:00 2001 > From: Masami Hiramatsu <mhiramat@xxxxxxxxxx> > Date: Mon, 23 Mar 2020 10:57:48 +0900 > Subject: [PATCH] ftrace/kprobe: Show the maxactive number on kprobe_events > > Show maxactive parameter on kprobe_events. > This allows user to save the current configuration and > restore it without losing maxactive parameter. > Hi Masami, Can you resend this patch as a stand alone (so that it shows up as a patch on the mailing lists). Thanks! -- Steve > Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> > --- > kernel/trace/trace_kprobe.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c > index 362cca52f5de..d0568af4a0ef 100644 > --- a/kernel/trace/trace_kprobe.c > +++ b/kernel/trace/trace_kprobe.c > @@ -1078,6 +1078,8 @@ static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev) > int i; > > seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); > + if (trace_kprobe_is_return(tk) && tk->rp.maxactive) > + seq_printf(m, "%d", tk->rp.maxactive); > seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp), > trace_probe_name(&tk->tp)); >
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